Handling nonconforming individuals in search-based model-driven engineering: nine generic strategies for feature location in the modeling space of the meta-object facility

Lately, the model-driven engineering community has been paying more attention to the techniques offered by the search-based software engineering community. However, even though the conformance of models and metamodels is a topic of great interest for the modeling community, the works that address model-related problems through the use of search metaheuristics are not taking full advantage of the strategies for handling nonconforming individuals. The search space can be huge when searching in model artifacts (magnitudes of around 10(150) for models of 500 elements). By handling the nonconforming individuals, the search space can be drastically reduced. In this work, we present a set of nine generic strategies for handling nonconforming individuals that are ready to be applied to model artifacts. The strategies are independent from the application domain and only include constraints derived from the meta-object facility. In addition, we evaluate the strategies with two industrial case studies using an evolutionary algorithm to locate features in models. The results show that the use of the strategies presented can reduce the number of generations needed to reach the solution by 90% of the original value. Generic strategies such as the ones presented in this work could lead to the emergence of more complex fitness functions for searches in models or even new applications for the search metaheuristics in model-related problems.